a) Field of the Invention
The invention is directed to a multiplex transmission device for multiple-channel signals, in particular multiple-channel audio signals, with a plurality of input channels, each of which receives an input signal, with a multiplexer, the input channels being connected with the inputs of the multiplexer, and with an output channel which is connected to the output of the multiplexer for sending an output signal which is multiplexed from the input signals. A control element is connected in each input channel for controlling the amplitude of the respective input signal and a regulating device is provided for controlling the control elements.
A device of this kind is used particularly for amplitude regulation and/or amplitude limiting of stereophonic audio signals, in which case the multiplexer is then usually a stereo coder.
b) Description of the Related Art
In known devices of this type, regulation was relatively involved since it had to be carried out for each input channel separately. The construction of the known regulating device was also correspondingly complicated; known regulating devices provided separate regulating amplifiers, rectifiers and timing circuits for devices provided separate regulating amplifiers, rectifiers and timing circuits for each individual input channel, although this could result in differential level errors. There was also an alternative construction, for example, with separate regulating amplifiers and rectifiers for each individual input channel and subsequent summation of the output signals of the rectifiers for a timing circuit.